1. Field of the Invention
The present invention relates to an optical disc device, and more specifically to a focus servo recovery processing method when defocusing or focus servo omission occurs during recording operation.
2. Description of the Related Art
For an optical disc device, a DVD in particular, a CLV (Constant Linear Velocity) method which rotates the disc at a constant linear velocity is employed at the time of data recording while a CAV (Constant Angular Velocity) method which keeps the disc rotation frequency constant is employed at the time of data reproduction. In such an optical disc device, when defocusing occurs at the time of data recording, retry processing is executed in which focus servo is applied again at the radial position where the defocusing has occurred. However, in a case where focus cannot be pulled in by this retry, pickup return processing is executed in which focus servo is applied again at the innermost circumferential position of the disc.
Published Japanese translation of a PCT application 2000-42608 describes that, in an optical disc reproducing device which performs by the CLV method reproduction from an optical disc on which recording has been performed by the CLV method, rotation control of a spindle motor is performed by the CAV method during processing at the time of reproduction from start of spin-up until reaching the reading standby state, thereby eliminating the need for operation of performing pull-in again by the CLV method even when defocusing of an optical head occurs, which permits achieving shorter waiting time for disc rotation, reduced seek time for the inner and outer circumferences, stable control, and reduced spin-up time.